Dexlansoprazole is chemically described as 2-[(R)-{[3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methyl}sulfinyl]-1H-benzimidazole as represented by Formula I.

U.S. Pat. Nos. 6,462,058 and 7,285,668 and U.S. Publication No. 2007/0004779 describe processes for preparing crystalline forms of dexlansoprazole and its hydrates. PCT Publication No. WO 2009/117489 describes processes for the preparation of amorphous dexlansoprazole.
U.S. Pat. No. 7,271,182 discloses the formation of alkali and alkaline earth metal salts—such as sodium, magnesium, lithium, potassium, calcium, and barium—of dexlansoprazole, by reacting dexlansoprazole with a metal hydroxide, a metal alkoxide or a metal amide. It further says that the reaction is usually carried out in the presence of an inert solvent or in the absence of a solvent altogether. It provides water, alcohols, ketones, nitriles, amides, ethers, esters, halogenated hydrocarbons, hydrocarbons, sulfoxides, polar solvents, and the mixed solvents of two kinds or more, as examples of inert solvents. U.S. Pat. No. 7,271,182 describes specific methods for preparing crystals of sodium, potassium and magnesium salts of dexlansoprazole from dexlansoprazole, which involve multiple isolation steps and treatments with solvents such as methanol, ethanol, isopropanol, water, diethyl ether, toluene, and t-butyl methyl ether. These methods mention the use of foamy or amorphous material of the above salts at crude stage.